American Transmission Co. will seek state approval for a $140 million project to run electrical power to the huge manufacturing complex Foxconn Technology Group plans to build in Racine County.

The massive plant is expected to draw an enormous amount of power — six times more than the next-largest factory in Wisconsin, according to ATC, which declined to identify that factory.

To provide that much electricity — enough to serve 170,000 households — the utility wants to run high-voltage power lines to a new substation it would build along Racine County Highway H just east of the Foxconn campus in the far southwestern corner of Mount Pleasant.

The project would affect the rates of residential electric customers in Wisconsin, but probably only marginally. ATC says the costs would be spread among some 5 million customers over 40 years.

"The typical residential customer would pay pennies per year over the life of the project," ATC spokeswoman Alissa Braatz said.

Before adding power lines and building the new substation, ATC will need approval from the State Public Service Commission. The utility says it will file an application with the PSC in February and ask for a decision by August.

If the commission approves the project then, construction would begin late next year on the substation and in early 2019 on the transmission lines, according to ATC. Power would start flowing by late 2019 or early 2020.

ATC does not operate power-generating plants. Rather, it owns and runs the high-voltage systems that deliver electricity. ATC is co-owned by Wisconsin utilities including We Energies, Wisconsin Public Service, Alliant Energy, Madison Gas & Electric and Superior Water, Light and Power.

To get power to Foxconn, ATC would add a second 345 kilovolt transmission circuit along 12 miles of existing lines from Pleasant Prairie north to Mount Pleasant.

That would take power to a point 1.2 miles east of the new substation. To connect the existing system to the substation, ATC would build new transmission lines, strung on 16 steel poles, 120 feet to 160 feet tall, set along an east-west corridor south of Braun Road.

The utility would need easements through the new corridor, either by negotiating with landowners or, if necessary, acquiring the right-of-way by exercising eminent domain authority.

ATC also would build an underground line beneath Highway H to connect to a Foxconn-owned power station on the factory site.

The state has approved up to $3 billion in incentives for the project. Racine County and the Village of Mount Pleasant have signed off on $764 million in assistance. Officials expect the local aid to be repaid over time by property taxes on the Foxconn complex and related development.

While the effect on individuals would be small, the $140 million ATC power project essentially would ask the public to contribute still more to Foxconn through higher electric rates.

"We’re trying to watch every penny because our rates are so high," said Thomas Content, executive director of the Citizens Utility Board of Wisconsin, an advocacy group for utility customers.

Foxconn also likely will be able to buy its power at a discount. Under the legislation spelling out the state subsidies and the company's obligations, Foxconn will be able to buy electricity at "market-based" rates. Such wholesale pricing, which is available to large power customers, generally is substantially lower than what ordinary customers pay, Content said.

The regular industrial rates at WE Energies, for example, have exceeded eight cents per kilowatt-hour since 2013, according to a filing by CUB and the Wisconsin Industrial Energy Group with the PSC. Wholesale market rates from WE Energies over that period have ranged from 2.9 cents to 4.3 cents per kilowatt-hour, according to CUB.

The Foxconn plant is to be built on some 1,200 acres bounded by I-94 on the west, Highway H on the east, Braun Road on the north and Racine County Highway KR on the south.